The story of scientists discovering climate change is longer than many of us tend to imagine. We’ve had a sense that what humans do might effect the climate since Antiquity. Studies of glaciers in the mid 18th century got people wondering what had changed since the Ice Age. It was back in 1824 that French physicist Joseph Fourier first started talking about something called the ‘greenhouse effect’. He already knew the atmosphere protected us from the sun. What was new was the suggestion that the composition of this atmosphere might change, and that could lead to a warming of the Earth, a bit like a greenhouse warms its contents.

A few decades later, in 1861, Irish physicist John Tyndall identified the gases he thought might cause such an effect, including carbon dioxide. A keen mountaineer, Tyndall had a hands-on knowledge of Alpine glaciers and was drawn to the puzzle of their history. Based at London’s Royal Institution, he didn’t just sit in a lab on his own and write letters to other scientists. Rather, he devised public demonstrations, drawing huge crowds in both London and for international tours. He also had a great beard.

Kalman filtering and smoothing; dynamic linear models

I have used dlm almost exclusively, except when extreme efficiency was required. Since Jouni Helske's KFAS was rewritten, though, I'm increasingly drawn to it, because the noise sources it supports are more diverse than dlm's. KFAS uses the notation and approaches of Durbin, Koopman, and Harvey.

``The real problem is that programmers have spent far too much time worrying about efficiency in the wrong places and at the wrong times; premature optimization is the root of all evil (or at least most of it) in programming.''Professor Donald Knuth, 1974